For many private home owners and developers, it is a challenge to figure out how to properly install the vapor barrier on the ceiling. Such an insulating layer is needed to protect the insulation from the penetration of moisture from the room (for example, household fumes).
Moisture degrades the thermal insulation properties of the material, so a special barrier is placed on its way. As a rule, such work is performed by professionals. But the developer himself needs to know the basics and how the vapor barrier is used in the future.
Why do you need it
It is not enough to know how to properly lay the vapor barrier on the ceiling of a bathhouse or living space, you also need to understand why this is done. Many believe that if they do not plan to make a heated room out of the attic, then neither steam nor thermal insulation is needed. In fact, both are still necessary at least in order to reduce heat loss.
It's just that with an unheated attic, the heat-insulating layer canlay directly on the reinforced concrete floor or place it in the space between the wooden joists.
But regardless of this, vapor barrier material must be laid under the thermal insulation layer. It prevents steam from penetrating into other elements of the roofing cake, which is especially important for rooms with high humidity, including a bath or kitchen.
Due to the presence of this layer, mold and fungus do not appear on the wooden frame elements.
How the vapor barrier will be located
Which side to lay the vapor barrier on the ceiling and what is the layout of this layer worries many when installing a roofing pie. In fact, everything here depends on how the attic is used.
If an unheated room and space are not planned to be used somehow, then the material is laid only along the ceiling plane. In this case, the insulation does not need additional waterproofing or wind protection, although a hydrobarrier along the slopes is still arranged so that atmospheric precipitation does not penetrate.
If the attic will be used for storing things, for some household purposes, including drying clothes, then the insulation in the roofing pie must be closed with a vapor barrier on both sides. On pitched planes, waterproofing is still done.
Types of materials
Vapour barrier uses different types of materials, including:
- Film. This is the most simpleand cheap material. It is produced in rolls, based on viscose and cellulose fibers. The material has a porous structure, which made it possible to retain excess moisture. The thickness of the film can vary within 10-200 microns, the width can be 2.5-6 m. The material is suitable for covering both wall and ceiling surfaces. This is a fairly practical and reliable option for vapor barrier. The material can withstand high temperatures and humidity. Therefore, the correct installation of vapor barrier on the ceiling in the bath often involves the use of film material. But he has his shortcomings. Basically, this is a relative fragility. In addition, if high temperatures are applied for a long time, it may break down. Therefore, it is usually not used for the steam room itself, only for other rooms in the bathhouse.
- Kraft paper. It is a construction cardboard with a protective coating, most often - foil, less often - lavsan (such material is more expensive). It is mainly used for vapor barrier in rooms with normal humidity. Can also be used in the bath. But only for the rest room, not for the steam room.
- Membrane materials. Considered the most popular option. Their distinctive feature can be considered a special two-layer structure. In it, each layer performs its function - one prevents the penetration of fumes, while the second ensures air circulation.
- Coating materials. This group includes polymer-bitumen mixtures produced under industrial conditions. Can even be used forrooms with high humidity. After application, they polymerize, which makes it possible to obtain a durable wear-resistant vapor barrier layer that provides maximum protection against fumes, and in addition has high noise and heat insulation characteristics.
Sometimes foil materials are allocated to a separate group. In addition to the already mentioned variety of kraft paper, it is also a fiberglass vapor barrier and some other options.
Best vapor barrier materials
Despite the abundance of various insulating materials, most often in private construction, homeowners prefer two brands - Izospan and Dekker.
Despite the fact that they are produced using different technologies, they have one thing in common - ease of installation, which is often a key factor for such construction.
"Izospan" and its properties
Most often in private low-rise construction, membrane materials are used as the most practical and easy to install. One of these options is, for example, "Izospan". This is a special film on a polymer (more precisely, polypropylene) basis.
Produce films of different thicknesses and, accordingly, different degrees of strength. In any case, they provide effective protection of the thermal insulation material from the damaging effects of moisture.
The company produces several types of material: FS, FX, FB. In the first case, we are talking about a membrane based on polypropylene, onwhich is coated with a metallized coating, in the second - about foamed polyethylene, in the third - about a foil insulator made from kraft paper.
The choice depends on the purpose of the room itself.
Decker vapor barrier
Decker REFLEXX Aktiv type materials are considered good vapor barrier. They are used where energy efficiency is important and it is planned to install a layer of thermal insulation with a thickness of 250 mm or more.
Instead of the traditional aluminum foil coatings, a special sprayed layer with high reflectivity is used here. It is not subject to oxidation, increases the vapor and thermal insulation properties of the material.
The Decker Klimat Aktiv vapor barrier has also proven itself well. It does not have a reflective layer, but it still has the same good performance.
Many people are interested in how to properly install Decker vapor barrier on the ceiling. In general, the process occurs according to the algorithm described below. But special tapes are used to glue the material.
In no case should you take household adhesive tapes, only intended for professional use and branded. Ordinary ones can peel off pretty quickly.
Installation technology
Laying vapor barrier on the ceiling requires an integrated approach. This is the only way to prevent heat loss and protect roofing materials from moisture. Regardless of what type of insulating materials is used, such work is carried out in severalstages.
How to properly lay the vapor barrier on the ceiling:
- Preparation.
- Installation of waterproofing material.
- Laying the thermal insulation layer.
- Installation of vapor barrier.
- Final surface plating (done for decorative purposes).
Each of these stages has its own characteristics, taking into account the type of material used.
How film and membrane materials are installed
Before laying the vapor barrier on the ceiling, you need to carry out preparatory work. If this is not just an unheated room that will not be used, but an attic, then the preparatory work will take more time.
After all, you need to clean the surface of the base from dust and debris, level it by covering the cracks with the appropriate compounds, and then prime and dry this plane.
Preparatory work
Sometimes preparatory work involves more operations. For example, if necessary, it will be necessary to repair the beams of the ceiling. It is especially important for houses that have been in operation for a long time - in this case, it is necessary to check the integrity of all elements, carry out repairs, remove all traces of fungus and mold.
All wooden elements are treated with a flame retardant and fungicide to prevent contamination by microorganisms. This is equally important for old and new houses. At the same stage, all work on the installation of utilities is carried out.
Installation work
The installation algorithm for film materials is as follows:
- The film is pre-cut according to measurements, mounted on the ceiling with an overlap of strips (its value is 10-15 cm, no more), and then fastened using a construction stapler.
- The film is laid with a clean side to the insulation, the side with the logo will be outside.
- To make the joints strong and reliable, they use a special waterproof tape (for example, there is a good tape of the Ondutis brand), and those places that are adjacent directly to the passage elements need additional insulation. They are also glued with tape, but with higher characteristics.
- The vapor barrier film is laid loosely so that it does not stretch, even if the material sags slightly - even better, because this will provide a margin of safety in case of a sharp temperature drop.
- Wooden bars are installed on top of the film.
When everything is ready, you can start finishing work. Membrane materials are laid in a similar way.
Laying vapor barrier in the bath
In this room, with a combination of high temperatures and humidity, vapor barrier is especially important. Moreover, such work is carried out both for the ceiling, and for walls and floors. Additionally, surfaces can be treated with protective compounds.
But how to properly lay the vapor barrier on the ceiling in the bath, only a few know. These jobs are usually done in the following order:
- Preparing the log ceiling. To do this, it must be sheathed with boards (recommended thickness - 6 cm). A foil material is fixed over such a crate (a thickness of 100 microns is enough).
- Evenly softened clay is applied to the foil layer and the selected vapor barrier material is laid on top.
- A heat-insulating material is laid on the layer described above, mineral or bas alt wool is usually used for a bath (recommended thickness is 5 cm). Sometimes seamless insulation is recommended. In such cases, choose ecological cotton wool or expanded clay.
- A moisture-proof membrane is also installed on the insulating layer, which is an additional preventive measure.
In the bath, the vapor barrier of the roof is also necessarily carried out, that is, the insulation is closed from moisture on both sides.
Laying vapor barrier: important points
Proper installation of ceiling insulation requires knowledge of some of the nuances of working with such materials.
Firstly, you need to take care of the vapor barrier, in no case should you pierce such material with nails. The stapler and tapes mentioned above are used to avoid damaging it.
Secondly, a ventilation gap of at least 5 cm should be provided between the film or membrane material and the decorative finish. This is important for rooms with high humidity, as well as for country houses that do not heat constantly during the cold season, but periodically.
At the same time, where the vapor barrier material intersects with the chimney, care must be takenabout the tightness of the joints. Then the whole system will last a long time and be quite effective.
